Response of Cells to Ionizing Radiation
Pp. 204-262 (59)
Wei Han and Kwan Ngok Yu
Ionizing radiation is encountered in our natural environment and is also generated and used
by mankind, e.g., for medical uses. A better understanding of the biological effects of ionizing
radiation will lead to better use of and better protection from radiation. In this chapter, the response of
cells to radiation will be described and discussed. Some basic concepts of ionizing radiation will be
briefly given in the beginning. The significant consequences of various types of radiation-induced
DNA damages show that DNA is the principle target for biological effects of radiation. The
misrepaired or unrepaired DNA damages, in particular DNA double strand breaks, will induce
chromosomal aberrations and gene mutations. On the other hand, radiation-induced DNA double
strand breaks play an important role in the induction of apoptosis and cell cycle arrest. Radiationinduced
bystander response, adaptive response and genomic instability are currently “hot-pots” in the
radiobiological research. These three phenomena indicate the complexity of cellular responses to
radiation, and will be introduced and discussed in this chapter.
Department of Physics and Materials Sciences, City University of Hong Kong, Hong Kong.